1. Technical Field
The present invention relates to an ultrasonic device as well as a probe, an electronic apparatus, an ultrasonic imaging apparatus, and the like using the same.
2. Related Art
As disclosed in, for example, JP-A-2007-235795, with regard to a so-called bulk-type ultrasonic transducer element, an acoustic matching layer that is in close contact with the surfaces of bulk piezoelectric bodies has been proposed. The acoustic matching layer is divided into pieces respectively corresponding to the piezoelectric bodies. A joint sealing material is filled in a space between adjacent acoustic matching pieces. The acoustic impedance of the joint sealing material is smaller than the acoustic impedance of the acoustic matching body. The joint sealing material has the function of preventing crosstalk between adjacent acoustic matching pieces.
In JP-A-2007-235795, silicone rubber containing filler is used as the joint sealing material. Silicone rubber has moisture permeability. Therefore, moisture passes through the silicone rubber to reach an electrode. The electrode is exposed to moisture. There is a fear that exposure of the electrode to moisture for a prolonged period of time may cause corrosion of the electrode and an increase in electric resistance.